| 1. |
- Berntson, L., et al.
(författare)
-
Construct validity of ILAR and EULAR criteria in juvenile idiopathic arthritis : a population based incidence study from the Nordic countries. International League of Associations for Rheumatology. European League Against Rheumatism
- 2001
-
Ingår i: Journal of Rheumatology. - 0315-162X .- 1499-2752. ; 28:12, s. 2737-43
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: New classification criteria (ILAR) have been proposed for juvenile idiopathic arthritis (JIA). They are more descriptive than those formerly used [American College of Rheumatology (ACR), European League Against Rheumatism (EULAR)], but require validation against classifications already in use. We validated the ILAR criteria in relation to the EULAR criteria in a prospective, incidence, and population based setting, and analyzed their feasibility. METHODS: Construct validity of ILAR and EULAR classification criteria refers to how closely the 2 instruments are related and how each of them operates in classifying subgroups/categories. Twenty doctors in 5 Nordic countries collected data from the incidence cases within their catchment areas during an 18 month period beginning July 1, 1997. Clinical and serological data from the first year of disease were collected. RESULTS: A total of 322 patients were included. Classification according to the ILAR criteria was possible in 321 patients; 290 patients had a disease duration > or = 3 months and were classified according to the EULAR criteria. One child could only be classified according to the EULAR criteria. Thus, 31/322 (9.6%) children were classified according to the ILAR criteria only. Forty-eight of 321 (15%) patients did not fit into any category and 6% (20/321) fulfilled criteria for2 categories. In the ILAR classification 5 out of 7 categories/subgroups have 2 to 5 specified exclusion criteria that highly discriminate the definition of each patient. In our study the exclusion criteria were fulfilled to only a small extent. CONCLUSION: The EULAR and ILAR criteria differ concerning the operational definitions of the subvariables involved, which complicates their comparison. By using ILAR rather than EULAR criteria the number of cases with juvenile arthritis increased by 10%, considering the first half-year after onset. The validity of the ILAR criteria is low since they often exclude patients from subgroup classification and the possibility of having more than one diagnosis is not negligible. The specified exclusion criteria for some of the subgroups are difficult to fulfill in clinical work and variables involved could be questioned with regard to their consistency.
|
|
| 2. |
- Berntson, L., et al.
(författare)
-
Incidence of juvenile idiopathic arthritis in the Nordic countries : A population based study with special reference to the validity of the ILAR and EULAR criteria
- 2003
-
Ingår i: Journal of Rheumatology. - 0315-162X .- 1499-2752. ; 30:10, s. 2275-2282
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To find the incidence of juvenile arthritis according to the ILAR and EULAR criteria within defined areas in the Nordic countries, and to study the validity of the ILAR and EULAR criteria from this perspective. METHOD: A longitudinal, prospective, population based study with patients enrolled according to the ILAR and EULAR criteria. Twenty doctors in Iceland, Norway, Sweden, Denmark, and Finland collected data from the incidence cases within their catchment areas over a period of 1.5 years, beginning July 1, 1997. Clinical and serological data from the first year of the disease were collected. RESULTS: In the whole group of 315 patients, the incidence rate was 15 per 100,000 children/year (95% CI 13-17) according to the ILAR criteria, varying from 7 (1-13) in Iceland, 19 (7-31) and 23 (10-36) from 2 different regions in Norway, and 9 (5-12) and 16 (9-23) from 2 different areas in Denmark, to 15 (12-18) in Sweden and 21/100,000/year (15-26) in the Helsinki region in Finland. An early peak in distribution for age of onset was found in girls but not in boys. The number of antinuclear antibody (ANA) positive children in the whole group, made up of children who had undergone at least one analyzed ANA test, was 123/315 (39%). Girls were ANA positive in 83/197 (42%) and boys in 40/118 (34%). Uveitis developed in 27/315 (8.6%) children during the first 6 months of the disease. CONCLUSION: Incidence rates of juvenile arthritis for areas within the Nordic countries were in accord with previous data. The ILAR criteria present slightly higher incidence rates, with a shorter disease duration for inclusion, compared to the EULAR criteria. Patients in one subgroup in either of the criteria sets do not necessarily belong to the expected subgroup in the other set of criteria; e.g., for juvenile ankylosing spondylitis (EULAR) and enthesitis related arthritis (ILAR). Our epidemiological findings are a reminder to be aware of possible new subgroups in children with juvenile arthritis.
|
|
| 3. |
- Berntson, L., et al.
(författare)
-
The influence of heredity for psoriasis on the ILAR classification of juvenile idiopathic arthritis
- 2002
-
Ingår i: Journal of Rheumatology. - 0315-162X .- 1499-2752. ; 29:11, s. 2454-2458
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To evaluate how heredity for psoriasis influences classification according to the International League of Associations for Rheumatology (ILAR). Heredity for psoriasis is currently both an exclusion and an inclusion criterion for different types of childhood arthritis according to ILAR classification criteria. METHODS: Twenty physicians in 5 Nordic countries prospectively collected data from the incident cases in their catchment areas over an 18 month period beginning July 1, 1997. Clinical and serological data from the first year of disease were collected. RESULTS: Of the 321 patients included who could be classified according to ILAR criteria for childhood arthritis, 50 (15.6%) patients were excluded from 55 classification events and fulfilled criteria for "other arthritis 1" i.e., did not fulfill criteria for any of the other classification categories, primarily because of heredity for psoriasis. If psoriasis in second degree relatives was disregarded as an exclusion criterion, only 8.7% of the patients remained in the "other arthritis 1" subgroup. For 20.6% of the whole group, heredity for psoriasis in a first or second degree relative (or both) and its distribution among arthritis subgroups did not differ except for juvenile psoriatic arthritis. CONCLUSION: We suggest that second degree heredity for psoriasis be withdrawn as an exclusion criterion from the ILAR criteria.
|
|
| 4. |
- Carlsson, A., et al.
(författare)
-
Receiver Model Including Square-Law Detection and ISI from Arbitrary Electrical Filtering
- 2003
-
Ingår i: Conference on Optical Fiber Communication, Technical Digest Series. ; , s. 68-69
-
Konferensbidrag (refereegranskat)abstract
- A dynamic receiver model, which uses the electrical filter time response to include the effects of inter-symbol-interference (ISI) was described. The model consisted an arrayed waveguide grating (AWG), a photodiode (PD), an electrical low pass filter (LPF) and a decision circuit. The model used matrix formalism, which made it directly applicable to numerical simulations. An example, measurements and numerical results on 10Gbit/s simulations, that showed the influence of ISI from a 4th order Bessel filter on the Bit Error Ratio (BER) was also presented.
|
|
| 5. |
- Carlsson, A., et al.
(författare)
-
Rigorous modeling of noise and ISI in optical WDM receivers with arbitrary electrical filtering
- 2002
-
Ingår i: Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest. ; , s. 532-533
-
Konferensbidrag (refereegranskat)abstract
- Rigorous modeling of noise and intersymbol signal interference in optical wavelength division multiplexing receivers with arbitrary electrical filtering was presented. Simulations of a WDM back-to-back system was performed with 32 signal channels. Bit-error-rate was evaluated as a function of received power at the input to the pre-amplifier. Results indicated that for a filter with a narrow bandwidth, the impulse response was spread out, and the detected bit was affected by the impulse response from previous bits.
|
|
| 6. |
- Jacobsen, Gunnar, et al.
(författare)
-
New rigorous model for Rx ISI effects in WDM systems
- 2004
-
Ingår i: Journal of optical communications. - 0173-4911 .- 2191-6322. ; 25:6, s. 241-45
-
Tidskriftsartikel (refereegranskat)abstract
- We present a model for Rx ISI effects using a new and completely general and rigorous dynamic Rx model for-mulation aiming at 10–40 Gbit/s WDM system design applications. The signal shaping part of an electrical fil-ter is modelled in the optical domain using the filter impulse response to modify the signal vector and the covariance matrix. In this way inter-symbol-interference (ISI) effects from any type of electrical filter – specified by the filter impulse response – can be described. The formulation leads to a Hermitian form of the covariance matrix, thus allowing a straightforward analytical formu-lation of the moment generating function (MGF) which in turn specifies the bit-error-ratio (BER). Numerical ex-amples for a 10 Gbit/s pre-amplified Rx shows that the ISI leads to (up to) several dBʼs degradation in sensitivity. Thus it is imperative to account for the Rx ISI effect in rigorous and accurate form in any general WDM trans-mission model.
|
|
| 7. |
- Malomed, B. A., et al.
(författare)
-
Propagation of an optical pulse in a fiber link with random-dispersion management
- 2001
-
Ingår i: Journal of the Optical Society of America. B, Optical physics. - : Optical Society of America (OSA). - 0740-3224 .- 1520-8540. ; 18:9, s. 1243-1251
-
Tidskriftsartikel (refereegranskat)abstract
- A model of a long optical communication line consisting of alternating segments with anomalous and normal dispersion, whose lengths are picked randomly from a certain interval, is considered. As the first stage of the analysis, we calculate small changes in parameters of a quasi-Gaussian pulse passing a double-segment cell by means of the variational approximation (VA) and we approximate the evolution of the pulse passing many cells by smoothed ordinary differential equations with random coefficients, which are solved numerically. Next we perform systematic direct simulations of the model. Simulations reveal slow long-scale dynamics of the pulse, frequently in the form of long-period oscillations of its width. It is thus found that the soliton is most stable in the case of zero path-average dispersion (PAD), less stable in the case of anomalous PAD, and least stable in the case of normal PAD. The soliton's stability also strongly depends on its energy, the soliton with low energy being much more robust than its high energy counterpart.
|
|
| 8. |
- Öhman, F., et al.
(författare)
-
Measurements of non-linear noise re-distribution in an SOA
- 2004
-
Ingår i: Conference on Lasers and Electro-Optics, 2004. (CLEO)..
-
Konferensbidrag (refereegranskat)abstract
- Measurements of the noise statistics after a semiconductor optical amplifier (SOA) demonstrate non-linear noise re-distribution with a strong power and bandwidth dependence.
|
|
